The invention relates to a device for connecting a first elongate member to a transverse second elongate member and is particularly, but not exclusively, concerned with a device for connecting together scaffolding tubes.
Over the years, various types of connectors have been proposed for interconnecting scaffolding tubes. In one arrangement, a locator on one of the tubes co-operates with an end section of the tube to be connected thereto and a wedge element is inserted and hammered into position to secure the end section to the locator. Examples of such systems are described in UK Patent Application Ser. No. 2 236 373, WO82/02733, U.S. Pat. Nos. 4,445,307, 4,273,463 and 4,180,342. The wedge system has drawbacks, in particular the need for a separate wedge element which can be dropped or lost. U.S. Pat. No. 5,078,532 does not involve the use of a wedge but a separate pin-like retainer is required to hold a movable latch member in its locking position.
In another system described in U.S. Pat. No. 3,992,118 a rotary clamping bush is provided on a vertical scaffolding member which is arranged to retain tongues provided on horizontal scaffolding member. The drawback with such a system is that where several horizontal scaffolding members are to be secured to the vertical member, all the horizontal members have to be correctly positioned before the clamping bush is rotated to clamp the tongues in position. Therefore, it follows that it is not possible to release and re-position one of the horizontal members without also releasing the others which can be undesirable particularly if the others are load bearing. An object of the present invention is to provide an improved type of device which can be used to interconnect scaffolding tubes and other elongate members.
According to the invention there is provided a device for connecting a first elongate member to a transverse second elongate member, the device comprising a locator on the first member for locating an end section of the second member, a movable locking means on the second member and an operating member which enables the locking means to be moved from a position in which the end section is locked in position on the locator by the locking means to a further position in which the locking means permits the end section to be separated from the locator, the operating member being a rotary member mounted on the second member and having a surface thereon which co-operates with the locking means whereby rotation of the rotary member effects movement of the locking means. The use of the rotatable operating member provides a secure connecting device which does not require the use of loose wedges or pins and which is simple to operate and enables individual second members to be connected to and disconnected from the first member without disturbing others.
Preferably, the operating member is mounted on the second member for rotation, e.g., about the longitudinal axis of the second member.
The operating member may be sleeve-like.
In a preferred embodiment, the operating member co-operates with a section of the locking means in a cam-like manner. Preferably, movement of the operating member relative to the locking means to lock the end section in position on the locator causes a cam-like surface on the operating member to displace a co-operating section of the locking means. Preferably, two opposite cam-like surfaces are provided one of which moves the locking means towards a locked position when rotating the operating member in one sense and the other of which moves the locking means towards an unlocked position when rotating the operating member in an opposite sense. In that way, both a positive locking and unlocking movement of the locking means is provided by the cam-like surfaces so that there is reduced likelihood of the locking means sticking in its locked position when disconnection of the elongate members is required
Where the operating member is in the form of a sleeve, the cam-like surface may be defined by a circumferentially extending slot in the sleeve, the slot also extending axially of the sleeve whereby rotational movement of the sleeve about its axis will cause the surface of the slot to displace the co-operating section of the locking means. Preferably, one surface of the slot displaces the co-operating section of the locking means in a locking direction during rotation of the sleeve in one sense and an opposite surface of the slot displaces the co-operating section of the locking means in an unlocking direction during rotation of the sleeve in an opposite sense.
The locking means is preferably arranged to move into a locking position such that a locking surface of the locking means lies adjacent part of the locator with the locator disposed in captive-manner between the locking surface of the locking means and the end section of the second elongate member.
Preferably, the operating member is movable between limits of travel and causes the locking means to move into a locking position before reaching one of its limit of travel. Further movement of the operating member up to that limit of travel then causes a locking force to be exerted on the locking means to clamp the locator between the end section and the locking means.
The locking means is preferably in the form of a lever pivotally mounted, e.g., on the second elongate member adjacent the end section. The locking means may be pivotally mounted on a carrier on the second member. The carrier is preferably integral with the said end section of the second member. In such a case, the end section is preferably axially spaced from the adjacent part of the second member and the aforesaid carrier is disposed therebetween.
The locking means is preferably mounted within a slot in the carrier and part of the locking means may project through the slot for co-operation with the operating member.
Where the locking means is mounted on the carrier, the operating member may be in the form of the aforesaid sleeve which is also mounted on the carrier, the sleeve being rotatable around the carrier for co-operation with the locking means.
If desired, secondary lock means may be provided to prevent unwanted movement of the operating member once the operating member has moved the locking means into a position where the end section is locked in position on the locator.
The secondary locking means may comprise a releasable member which, in a locking position, engages the operating member to prevent movement thereof and which, in a release position, permits movement of the operating member.
The releasable member may be resiliently biased into a locking position.
The secondary locking means may be provided on the aforesaid carrier for co-operation with the said operating member.
The said releasable member may comprise a resiliently mounted radial projection which extends past an edge of the operating member, e.g. an edge of an aperture in the operating member, to prevent movement of the operating member and which is displaceable to permit movement of the operating member.
An unlocking device, e.g. in a form of a wrench, may be provided for moving the secondary locking means from a locking position to or towards a release position. The unlocking device may include a first section arranged to locate on part of the operating member and a second section provided with a surface which is arranged to move the secondary locking means from its locking position to or towards its release position. In one embodiment the unlocking device displaces the secondary locking means into its release position whilst in another embodiment the unlocking device displaces the secondary locking means towards its release position and the operating member is formed with a ramp-like surface which, on rotation of the operating member to release the locking means, further displaces the secondary locking means into its release position.